Laundry machine



L. M. KAHN LAUNDRY MACHINE Nov. 7, 1950 SSheets-Sheet 1 Filed Aug. 10, 1945 INVENTOR.-

Nov. 7, 1950 M. KAHN 2,528,594

LAUNDRY MACHINE Filed Aug. 10, 1945 5 SheetsSheet 2 L. M. KAHN LAUNDRY MACHINE Nov. 7, 1950 5 Sheets-Sheet Filed Aug. 10, 1945 INVENTOR: L :0 Kafin L. M. KAHN LAUNDRY MACHINE Nov. 7, 1950 5 Sheets-Sheet 5 Filed Aug. 10, 1945 Ill-III INVENTOR. Leo/l A An V n ,IIIIIIIlIIIIIIIIIIIlll|||llllllllllull.IIIvIIIIIIIIII II IIIIIIII II II UNITED S ATES PATENT ornca I 2.52am

lieorxrhlandlarhnt Application Alli-It 1., 1945, sel'lalnn. 810,.35

Claims.

This invention relates to laundry machines and more particularly to a laundry machine incorporating damp drying features through the centrifugal extraction of moisture.

This application is a continuation in part of my former application for Cleaning or laundry machines died December 23, 1943, serial Number 515,356. In that application I described an apparatus and method for obtaining a symmertical and balanced distribution of the washed materials in the washing cylinder prior to high speed rotation thereof, for ejecting the wash water through centrifugal action. As disclosed in said application, the desired symmetry was obtained by varying the effective volume of the cylinder after washing so as to conform to the mass of the washed clothes. By thus causing the effective I volume to approach the size of the mass, the method inherently produces a state of symmetry and balance which permits the utilization of increased centrifugal force through high speed rotation without injury to the machine or objectionable vibration of its elements. Since this principle involves changing the volume of the cylinder after the washing operation to a degree commensurate with the bulk of the washed mass, I have used the term volumetric control to describe the action. It should be observed that volumetric control adapts the cylinder to the mass of the clothes after the clothes have been washed and that its incorporation in a washing machine imposes no limitations on the washing action.

I have discovered further that the principle of volumetric control may be applied to rinsing as well as to drying operations in that rinse water may be introduced with considerable effect into the balanced mass while it is undergoing high speed rotation. In order to take advantage of the superior rinsing results attainable by high speed rotation, many laundries make a practice of removing the washed clothes from the washing cylinder and re-loading them into a vertical type of rotating extractor whereupon the clothes are rotated at high speed while a stream of water is directed at them.

Bearing the foregoing in mind, it is an object oi'this invention to provide a washing machine which shall serve effectively as a centrifugal rinsing machine. The objective, moreover is not only to reduce the labor and inconvenience of re-loading operations but to provide a more satisfactory rinsing operation than heretofore achieved. This is realized by concentrating or localizing the clothes in an area where rinse water is supplied.

Another object of this invention is to provide a plurality of washing chambers having joint controls for washing, rinsing and drying the clothes, the rinsing anddrying controls being adaptable to mutually'varying conditions in each chamber and responding to their individual requirements.

Another object of this invention is to provide a mum-chambered washer having novel, emcient. and space conserving means for balancing the mass of washed clothes in each chamber prior to high speed rotation thereof whether for rinss. dry or both.

A further object of this invention is to provide automatic response when the desired distribution of the washed mass is achieved so that the cylinder is automatically brought into high speed rotation when conditions indicate that the clothes are properly disposed for the operations to follow.

It is a further object of this invention to provide a system whereby the commencement of high speed rotation is accompanied by the introduction of rinse water into the rotating mass and wherein such rinsing is continued for a predetermined period of time so as to be followed by damp drying extraction automatically.

Another object of this invention is to concentrate and shape the massed clothes in an area where rinse water is supplied whereby the rinse,

water is sprayed into the center of an annular mass of clothes so as to be forced through the clothes through centrifugal ejection.

Other objects of my invention will be apparent from the following description, it being understood that the above general statements of the objects of my invention are intended to describe and not to limit it in any manner.

Referring to the drawings.

Fig. 1 is an elevational view of a washing machine principally in cross-section as viewed along the lines l-l of Figs. 2, 3 and 4.

Fig. 2 is an end view of the machine as viewed from the line 2 of Fig. 1.

Fig. 3 is a cross section along the line 3-3 of Fig. l.

Fig. 4 is a composite, sectional view of the respective outer ends of.the cylinder taken on the lines 4-4 of Fig. 1.

Fig. 5 is a schematic operational view illustrating the position of the controls during the washing operation.

Fig, 6 is a schematic view similar to that of Fig. 5 and illustrating the machine as it prepares for high speed rotation.

The apparatus comprises an outer shell Iii supported by standards II and having trunnions II for rotatably supporting the multi-chambered washing cylinder i3. Cylinder I3 is formed with the usual perforations H and is divided by partition l5 into two chambers l6 and i1. Cylinder i3 is formed with hubs i8 and is located respectively at both ends thereof and is adapted for rotation on trunnions l2 by the anti-friction bearings 20.

Pulley 2| on hub I9 is driven by electric motor 22 through driving belt 21 so as to rotate the cylinder it at a slow, or washing speed. At the op- 3 posite end of the cylinder is disposed the'pulley 24 for rotation on the hub l2, the pulley 24 being driven by the electric motor 26 through the belt 26. Electric motor is a high speed motor for driving the cylinder l3 at water extraction speed. Motors 22 and 25 are selectively operative depending upon whether the washing or extracting operations are being conducted and the cylinder I3 is rotated at the speed appropriate for either of these operations.

Access to chambers l6 and H for loading them with clothes and washing materials such as soap, wash bleach and bluing, is provided by means of the doors 21 and 28 respectively. These doors are disposed so as to register with doors 26 and 30 formed in the shell l0. Latches 3| maintain the doors closed when the machine is in operation.

Cylinder I3 is provided with ribs 32 for the usual washing and agitating functions, the ribs 32 being spaced around the inner periphery of the cylinder l3. During the rotation ofthe cylinder the ribs serve to carry the washing clothes upwardly until the angle of repose is exceeded whereupon the clothes tumble back toward the bottom of the drum so as to become washed.

Wash water is introduced into the shell In by means of the water pipe 23, controlled by valve 34. The water thus introduced is admitted into cylinder |3 through its perforations M. In order to maintain the driving connections free of water, partitions 35 and 38 are provided, the central openings of which serve to embrace the respective hubs of the cylinder |3.

Means are provided in the machine to incorporate my principle of volumetric control. Thus, partitions 31 and 38 are arranged for controlled axial movement within the cylinder |3 so as to reduce the effective volume of the chambers after the washing operation has been completed. It is undesirable to maintain clothes in a tightly packed state. during washing because this condition prevents a tumbling action. Accordingly, the general practice is to avoid overloading of the washing cylinders in view of this requirement. I have determined that when extracting operations are conducted in the same machine, the resulting small volume of clothes relative to the cylinder makes it difflcult to secure a balanced distribution of the clothes. It is apparent, therefore, that the volume requirements of washing and extracting operations are conflicting. The use of volumetric control in the manner described, however, adapts a cylinder to the conditions required for each operation and by reconciling these differences, permits a single machine to perform both functions effectively.

Control partitions 31 and 38 are hydraulically driven by plungers which are disposed within ribs 32. Each control partition is driven by a plunger which is normally housed in a rib of the opposite chamber and the respective driving plungers of each partition are mutually laterally staggered. Thus, as illustrated in Fig. 4, each pair of plungers driving a partition operates a plane perpendicular to the other pair of plungers so as to minimize space requirements and retain cylinder balance.

Controlpartition 31 is actuated by plungers 39 and 4|! which are slidably arranged in hydraulic cylinders 4| and 42 formed by hollows in ribs 32. Plungers 39 and are secured as by rivets to the partition 31 and are formed with .pistons 43 and 44 adapted to be actuated by fluid under Pistons 48 and 50 on the plungers 46 and 46 are adapted to be actuated by fluid under pressure so as to drive the partition 38 axially of the chamber I6.

Referring to Figs. 4 and 5, the hydraulic pressure system comprises a storage tank 6| which may be supplied with water from the main supply 33 through a pipe 63 and controlled by a valve 64. Valve 64 will be opened only infrequently to replenish the fluid since the system is arranged to return exhaust fluid to the tank 6|.

A motor and pump combination 65 is provided to circulate fluid under pressure in the hydraulic conduits or pipes which feed the hydraulic cylinders. Thus, when electric switch 56 is closed, electric current from lines 51 and 66 energize the pump motor and the fluid is forced up pipe 59, through-two-way valve 66, through the hydraulic system returning finally through pipe 6| to the tank 5|. When the control partitions are to be moved inwardly in preparation for the rinsing and extracting operations to follow, valve handle 62 is adjusted so that the valve passages connect pipe 59 with pipe 63 and pipe 6| with pipe 64 as illustrated in Fig. 5. The fluid thereupon courses through the pipe 63 into the bore 65 of trunnion l2, through the four pipes 66, 81, 68 and 68. Pipe 66 communicates with hydraulic cylinder 42 so that partition 31 is forced outwardly to reduce the eilective volume of chamber l6. Simultaneously therewith, fluid from the pipe 61 enters hydraulic cylinder 41 while fluid from pipe 68 enters hydraulic cylinder 48 so that partition 38 is similarly forced outwardly to reduce the effective volume of chamber |1.-

Means are provided to restore the exhaust fluid to the tank 5|. Thus, hydraulic cylinder 4| has an opening 10 which communicates with pipe 1| so that the exhaust fluid is forced through pipe 1| to the bore 12 in trunnion I9, through pipe 64, into pipe 6| through the valve 68 and into the tank 51. Similarly, the openings 13, 14 and 15 of the remaining hydraulic cylinder feed pipes 16, 11 and 18 respectively so that the fluid reaches bore 12 whereupon it takes the return course above described.

Rinse water is provided not only through the main fill valve 34 but through sprays at the end of the cylinder l3. A pipe 18, leading from the main water supply 33 to the valve 80, serves to introduce water into the pipe 8|, through pipe 82 into the bore 83 and through the spray head 84 into the chamber |1. Pipe 8| also feeds pipe 85 which reaches spray head '86 through bore -81 and supplies spray rinse water to the opposite chamber l6.

An important function of the apparatus is to provide automatic shifting of the cylinder rotation into high speed when conditions indicate that the clothes have been distributed for balance. As will be hereinafter described, the amassing of'the clothes in the region of the spray heads 84 and 86 creates considerable resistance to the flow of rinse water from the pipes 82 and 85. Referring to Fig. 6, the arrows 88 in full lines indicate the course of the rinse water up to the spray heads while the arrows 89 in dotted lines indicate the return course of the rinse water as resistance is encountered due to the accumulation of clothes at the spray heads. Thus, the back pressure accompanying the concentration of the clothes at the ends of the cylinder l3 forces the water into pipe 90 and thence into the pressure switch 8|.

Referring to Fig. 5, which illustrates schematically the position of the pressure switch II and other controls durin the washing operation, the switch plate 02 is adapted to move to a. forward position in responseto fluid pressure thereagainst occasioned by the resistance set up at'the spray heads. Switch plate 02 is of metallic material and its forward motion serve to bridge the electrical contacts 02 and 04. Electric supply lines 00 and 00 not only serve to energize high speed motor 20 but they include solenoids 01' and 00 in a series arrangement for establishing or breaking the electrical circuits of both motors 22 and 20 as controlled by the pressure switch 0i. As will hereinafter appear, solenoid I02 is included in the series circuit established by the movement oi switch plate 02.

When contacts 00 and 04 are connected by the bridging action of pressure switch plate 02, the solenoids are energized. Plunger 00 of solenoid 00 is then pulled in to break the circuit of motor 22 so as to discontinue slow speed actuation of the cylinder I0, while plunger I00 of solenoid 91 is pulled in to establish the high speed circuit of motor 20. Thus, the position of the piled-up clothes is used to control the shifting of speeds. Since the spray heads 04 and 00 are of large diameter, being about one-half the diameter of the end wall and disposed centrally thereof, the accumulation of the clothes so as to block the perforations substantially assures a satisfactory radial distribution of the clothes and indicates that high speed rotation may be applied to the cylinder without the danger of excessive vibration from unbalance. It will be recognized that after such radial or circumferential distribution has been attained, the increased centrifugal force accompanying high speed rotation will effect a symmetrical expansion of the mass so as to form a concentrated annulus of increasing size until the inner periphery of the cylinder I3 stops further expansion. The circumferential uniformity of distribution thus realized will permit considerably higher speed of rotation to be employed than is permitted in prior art machines of like design. The benefits of high speed rotation are very highly regarded in the art because of the increased degree of drying made possible and, as recognized in recent time, the more'emcient rinsing operations which can be applied. The operation of pressure switch 9| may be regulated by adjusting its resistance to back pressure, if desired. This may be accomplished by regulating the spring tension which maintains it in the open position. Thus, it may be arranged to operate at an intermediate degree of distribution of the clothes with regard to the spray heads,

- The present apparatus includes, as a special advantage, mechanism for conducting a centrifugal action rinsing operation for an automatically limited period of time after high speed rotation has commenced. Thus pressure switch 0i includes a rigid, fixed plate I 0| of electrical insulating material such as Bakelite, upon which electrical contacts 03 and 04 are mounted. A pipe II2, branching oil pipe 03, leads into a chamber I I4 in pressure switch 9i. Solenoid I02 has a plunger I03 in the form of a valve so that the energizatlon of solenoid I02 causes fluid undeipressure to enter chamber II4. A plate H5 in chamber II4 operates as a plunger and moves forward in response to the fluid pressure to force fluid such as water or oil from the forepart of the chamber 4 into dash pot I04 through constriction I00. Plate H0 is adapted to travel between the limiting rings H0 and III, the direction depending upon the directlon of pressure exerted against it. The motion imparted to plate IIO when pressure fluid is introduced into chamber II4, forces the fluid from the forepart of the chamber, through the constriction I00 so as to move plunger I00 slowly through the dash pot I04. It will be recognized that the speed of movement of plunger I00 will be controlled by the opening of constriction I00. A valve member I0! is disposed at constriction I00 to vary the size thereof so that the time constant of the dash-pot may be adjusted to the desires of the operator.

The outward movement of plunger I00 causes its shaft to bear against valve 00 so as to close it and cut oil the supply of rinse water to the spray heads. Switch plate 02 is of the on-off type wherein the plate has two rest positions and the bridging of contacts 03 and 04 is effected through an on" rest position which remains established by the usual spring action until restored to inoperative position by manually actuated handle- I08. During both the rinsing and extracting operations, the dump valve I00 is in the open position of Fig. 6 so that wash or rinse water is drained from the shell. Rinse water valve 00 remains in the closed position until manually restored by the operator for the next load of clothes. Switch 50 is opened at this time to deactivate the pump unit and plunger I00 of the dash pot I04 is pushed back so as to restore plate I I5 to its original position.

At the completion of the extraction operation, switch handle I00 is adjusted to restore switch plate 02 to inoperative position. This deenergizes solenoids 0'! and 00 so that the cylinder I3 may resume slow speed operation for rea-- sons to be explained hereinafter. If visual access to the interior of the cylinder is desired during rotation, a window I09 may be formed in the shell I0 and the partitions or clothes may be visible through the perforations of the drum. Referring to theschematic views of Figs. 5 and 6, broken lines are employed generally to indicate those components which are not used for the particular phase of the operations illustrated.

The apparatus is operated in the following manner:

The dirty clothes and washing materials are loaded into both chambers of the cylinder I3 while valve 34 is opened until enough water is supplied. j Switch H0 is then closed to energize slow speed motor 22. The washing action is time. The position of the controls during the period is shown in Fig. 5 wherein the mass of clothes II I in the chamber I0 is illustrated as being smaller than the mass H2 in the chamber I! in order to demonstrate the adaptability of the machine to such conditions. After the washing operation dump valve I09 is opened to drain the wash water while valves 34 and 00 may be opened to supply rinse water from the top and sides of the device while the cylinder is rotating.

Switch 50 is then closed and valve 60 is adjusted to the position of Fig. 5 so as to drive the partitions 31 and 38 and reduce the effective volume of the cylinder. It is desirable to maintain a supply of water in the cylinder I3 during the compressing action of the partitions since the distribution is more effective when the bottom of the cylinder is well filled with water or when water is supplied to the clothes from another source. If the rinse water input in insumcient to maintain the supply in the cylinder, dump valve I may be closed and automatic float controlled solenoid means may control the opening thereof as is well known in the art. However, a steady stream from any source will be satisfactory, im-

clothes I I I has not as yet plugged the spray head 86. Accordingly, the spray water will take 1 the path to spray head 86 through pipe 85 since that path stilloii'ers no resistance such as has been created at spray head 84. Thus, the operation of pressure switch 9| will be delayed until both chambers have achieved the correct distribution in spite of the fact that the mass of the clothes in each chamber may vary.

The subsequent back pressure then operates pressure switch 9| so as to throw the cylinder into high speed rotation. This clears the clothes from the spray heads and forces the clothes into the shape of an annulus of pronounced symmetry and uniformity for reasons which have been described. The removal of the clothes from the spray heads does not restore switch 9| to open position since the switch is fixed in its second rest position wherein it closes the solenoid circuit.

The rinse water from the spray heads thus continues during high speed rotation so that the water is picked up as it emerges from the spray heads and is forced through the clothes which have been concentrated and localized by the partitions in the area where the spray rinse water is moving at high speed through centrifugal action. Rinsing continues for the duration of the time constant of dash pot I04 as controlled by constriction controlling valve I01.

The ensuing actuation of valve 80 cuts oil! the rinse water and permits the extraction operation to follow. This is permitted to continue for the desired time, usually about ten to fifteen minutes. The dash-pot mechanism is restored .to original position and switch handle I08 is then operated to restore switch plate 92 to the open position so that cylinder I3 resumes slow speed operation. This does not cause rinse water to fiow because valve 80 remains closed until manually opened. In re-setting the dash pot, valve I01 may be adjusted to permit unrestricted flow. Valve 60 is then adjusted after the pump unit is restored to operation so as to return the partitions 31 and 38 to their inoperative position. The release of the clothes by the partitions and the slow tumbling action serve to loosen the concentrated mass and facilitate removal from the cylinder.

Slow speed motor 22 is then stopped by opening switch H0 and the clothes are removed. When the next load of clothes is to be washed.

valve 00 may be manually restored to open p0 invention but it is obvious that numerous changes and omissions may be made without departing from itsspirit. For example, automatic means I for controlling the cycle of operations may be incorporated into the device as is well known in the art and as shown in many prior devices such as my co -pending application Serial No. 569,609, flied December 23, 1944.

I claim:

1. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, means for concentrating and localizing washed clothes in a portion of said cylinder during low speed rotation thereof, and control means disposed in said portion of concentration of said clothing and responsive to said concentration so as to effect a shift of rotation of said cylinder from low to high speed, th response of said control means being governed by the physical contact therewith of said concentrated clothes.

2. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a portion of said cylinder during low speed rotation thereof, a control member disposed in the portion of concentration of said clothing so as to be subjected to pressure by said concentrated clothing, and means responsive to said pressure for shifting said cylinder from low to high speed rotation.

3. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a limited portion ofsaid cylinder, a water supplyjected to pressure by said concentrated clothing,

said water supply member being formed with water outlet means adapted to be plugged by said concentrated clothing and means responsive to said plugging for effecting high speed rotation of said cylinder.

4. In a washing and drying machine having a cylinder rotatable at low speedfor washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a limited portion of said cylinder during low speed rotation thereof, a, rinse water supply member disposed in said cylinder at said portion of concentration of clothing so as to be subjected to pressure by said concentrated clothing, and means responsive to said pressure to shift said cylinder into high speed rotation whereby said clothing is thrown radially outwardly of said rinse water supply member by centrifugal force so as to permit rinse water therefrom to be in- J'ected centrally of said clothing.

5-. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a limited portion of said cylinder, a water supply member disposed in said cylinder at said portion of concentration of clothing so as to be subiected to pressure by said concentrated clothing,

said concentrated clothing, and a pressure switch operated by back pressure resulting from said plugging for effecting high speed rotation of said cylinder.

6. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a portion of said cylinder, a control member disposed in the portion of concentration of said clothing so as to have its outer surface subjected to pressure by said clothing, said control member having a diameter approximately one-half that of said cylinder whereby distribution of said pressure on the outer surface of said control member represents a substantial degree of radial distribution of said clothing in said cylinder and means responsive to said distribution of pressure on said control member for effecting high speed rotation of said cylinder.

7. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for centrifugal drying operations, a compression member for concentrating and localizing washed clothing in a portion of said cylinder, a control member disposed in the portion of concentration of said clothing so as to have its outer surface subjected to pressure by said clothing, said control member being centrally disposed of said cylinder on a transverse wall thereof and having a diameter approximately one-half that of the cylinder whereby distribution of said pressure on said outer surface of said control member represents a substantial degree of radial distribution of said clothing in said cylinder and .means responsive to said distribution of pressure on said control member for effecting high speed rotation of said cylinder.

8. A washing and drying machine according to claim 7 wherein said control member is a Water outlet member.

9. A washing and drying machine according to claim 8 wherein said control member comprises a rinse water supply member having water outlet openings formed over its entire outer surface, the pressure of the concentrated clothing serving to produce a back pressure at said control member by plugging said outlet openings, said distributed pressure responsive means comprising a pressure switch adapted to be actuated by said back pressure to shift said cylinder into high speed rotation so as to form said clothing into an annulus and to release saidoutlet open-'- ings for permitting rinse water to be supplied centrally of said annulus.

10. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for drying operations, a pair of individual chambers in said cylinder, a movable partition in each of said chambers for reducing the effective volume of said chambers after said washing operations and drive means for each of said chambers, said drive means for each chamber comprising an actuating plunger normally housed in the other of said chambers.

11. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for drying operations, a pair of individual chambers in said cylinder, a movable partition in each of said chambers for reducing the eflective volume of said chambers after said washing operations and drive means for each of said chambers, said drive means each comprising a pair of plungers operative at diametrically opposite points on said partitions, each .pair of plungers being radially staggered in respect to the other pair.

12. An apparatus according to claim 11 wherein each pair of plungers actuating a movable partition in one chamber, is normally housed in the other chamber.

13. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a relatively higher speed for centrifugal drying operations, a compression member movable axially of said cylinder for concentrating Washed clothes in a limited portion of said cylinder prior to high speed operation, a pressure responsive member axially located in said cylinder and operative to effect high speed rotation of said cylinder when subjected to pressure by the concentrated clothes, said pressure responsive member being operative to supply rinse water for said washed clothes whereby the high speed rotation of said cylinder forms said clothes into an annulus and permits said rinse Water to be injected centrally of said annulus, and means to interrupt the injection of said rinse water after a predetermined period of time so as to permit the water to be extracted from the clothes through centrifugal action.

14. In a washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for drying operations and having peripherally disposed agitating ribs, a pair of individual washing chambers in said cylinder, a movable partition in each of said chambers for reducing the effective volume of said chambers after said washing operations, and drive means for each of said partitions, said drive means comprising plungers housed in ribs of said cylinder and means to actuate said plungers, each of said plungers being housed in a rib disposed in the chamber opposite to that of the partition driven by said plunger.

15. In a, washing and drying machine having a cylinder rotatable at low speed for washing operations and at a high speed for drying operations and having peripherally disposed agitating ribs, a pair of individual washing chambers in said cylinder, a movable partition in each of said'chambers for reducing the effective volume of said chambers after said washing operations, and drive means for each of said partitions, said drive means comprising plungers housed in ribs of said cylinder and means to actuate said plungers, each of said plungers being housed in a rib disposed in the chamber opposite to that of the partition driven by said plunger, each said pair of plungers operating in a plane perpendicular to the other pair of said plungers.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 452,129 Garrison May 12, 1891 2,035,481 Hume Mar. 31, 1936 2,161,604 Watts June 6, 1939 2,187,770 Chamberlin Jan. 23, 1940 2,274,121 Bendix Feb. 24, 1942 2,302,836 Breckenridge Nov. 24,1942 2,356,818 Bruckman Aug. 29, 1944 2,381,974 Emerson Aug. 14, 1945 

